Applied patch from jira issue - OFBIZ-3464 - Added check if the credi…

…tcard number string is numeric in validation method isCreditcard in UtilValidate.

Thanks Nils for creating the issue and providing the patch for the same. Thanks Divesh for your help in verification. 

git-svn-id: https://svn.apache.org/repos/asf/ofbiz/trunk@1649393 13f79535-47bb-0310-9956-ffa450edef68

framework/base/src/org/ofbiz/base/util/UtilValidate.java

@@ -1052,7 +1052,9 @@ public static String appendCheckDigit(String stPassed) {
     public static boolean isCreditCard(String stPassed) {
         if (isEmpty(stPassed)) return defaultEmptyOK;
         String st = stripCharsInBag(stPassed, creditCardDelimiters);
-
+
+		if (!isInteger(st)) return false;
+
         // encoding only works on cars with less the 19 digits
         if (st.length() > 19) return false;
         return sumIsMod10(getLuhnSum(st));